With the rapid popularization of flat panel display products such as liquid crystal displays (LCDs), organic light emitting diode (OLED) displays and the like, the requirements for color display are increasingly improved. Color filters are critical components for the flat panel display products such as LCD panels and OLEDs to achieve colorful display.
A coloring photosensitive resin composition is a photosensitive resin composition comprising coloring pigment(s), which is useful for forming color patterns (including red, green, blue, yellow, orange, black, etc.) of color filters. There are many methods for preparation of color filters, such as dyeing process, pigment dispersion process, printing process, etc. The pigment dispersion process comprises the steps of: coating a coloring photosensitive resin composition onto a color glass substrate provided with a black matrix; performing photolithography including exposure and development to form the first color pattern of a color filter, followed by treatment including heating; repeating the steps described above to form all the color patterns of the color filter; and finally forming a conductive layer of indium tin oxide, thereby the finished color filter having multi-color patterns can be obtained.
Since color filters for flat panel display products are desired to exhibit relatively high transmittance and low light-scattering, the coloring photosensitive resin compositions for preparing the color filters should have stable dispersions of particles and particle size distributions. Conventional coloring photosensitive resin compositions useful for the color filters typically comprise unsaturated carboxylic acids or carboxylic anhydrides, resins comprising ethylenically unsaturated double bonds and epoxy groups, pigments, dispersants, photoinitiators, solvents, etc. However, such coloring photosensitive resin compositions encounter some problems. For example, the viscosity of the coloring photosensitive resin compositions increases and the flowability thereof decreases, post-thickening phenomenon occurs over time, curing may be insufficient, and so on. In return, the surface characteristics of the resulting color filters are affected.
There are some reports of photosensitive resin compositions. For example, CN102253599B discloses a salt-forming product prepared from a xanthene-based acidic dye and a cationic group-containing compound. The product may overcome the shortcomings of acidic dyes including poor heat resistance, light resistance, and solvent resistance, and may improve the transmittance of color filters.